Bicycle frame



FIG. 1 is a front perspective view of a bicycle frame according to my design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a front view thereof;

FIG. 6 is a rear view thereof;

FIG. 7 is a top view thereof; and,

FIG. 8 is a bottom view thereof.

The broken lines inside the frame tubes illustrate the boundaries of the claimed design, while the other broken lines illustrate environmental structure. None of the broken lines form part of the claimed design. 

The ornamental design for a bicycle frame, as shown and described. 